Due to the slim PS2s lacking the ability to connect a hard drive, mods have been designed to restore that functionality.
700XX Models
You can manually wire up the connector with the Automan mod using the image on the right, but equivalent kits do the same. Some available kits as of 2026-02-14 are the Arithmus iFlash2PS2 and Gusse IDE Resurrector.
On these models, the HDD is not natively bootable, but FMCB can restore that functionality.
Previous mods included the HD Connect and a more premium version, the HD Combo, which included a case replacement to house the drive. They were both available from MaxDiyPower.com until mid-2020. In 2018, two high-performance external storage products known respectively as PS2NetBox and PS2USB2.0 were manufactured by ABitTop.com for a short time. They are not recommended because, being original designs, they also require explicit software support, and support for their closed-source OPL and POPStarter mods was quickly dropped.
750XX and Higher Models
750XX and higher models do not intrinsically support any disk interface. Third-party accessories like the HD Pro can connect a disk, but performance will be severely limited, and compatibility will be restricted to software designed for the specific interface.
Using Non-Official Drives
Only Sony-brand disks will be supported by official drivers, unless an ATAD patch (ATAD is the name of the HDD driver) is applied. Of course, this is not practical with original game discs, and backups loaded from HDD can't access the disk for their purposes in the first place. Homebrew drivers do not have this limitation.
Be wary of a claimed IDE emulator for the PS2 under the name of 3do.dev or Fixels, as it has proven to be a scam.
Additionally, the exact position of power and data connectors on 3.5 inch IDE disks is not standardized and the movements of the Network Adapter's plugs may not be sufficient, unless partially disassembled to leave them loose. Maxtor and Seagate drives, the OEMs for Sony, tend to fit the best.
Using Drives Over 137 GBs
As the only official disks are 40 GB, and part of the HDD drivers had to be finished before the Western launch (to support booting from the hard drive), the official drivers only support 28-bit LBA addressing, therefore up to 137 GBs. LBA48 patches are available, with the caveat listed above, for official drivers, and most newer homebrew support LBA48 out of the box. However, care must be taken not to mix LBA48 and LBA28 software to avoid corruption due to partitions crossing the limit of LBA28.
Additionally, due to the intrinsic design of the PS2's APA partition scheme (not using a conventional partition table, requiring a linear scan of the disk to determine its contents), exacerbated by the lack of cache that can be implemented in what's left of the 2 MB IOP memory after loading all other drivers, and of the inefficient method for doing said search, severe performance issues will be experienced after exceeding a certain number of partitions, very roughly approximable to 80-120 GB.
Recent versions of OPL use a list of installed games that is manually updated on demand to mitigate the problem, but this does not apply to any other software. The workaround is to go solid state.
Further, software that is LBA48 compatible but uses signed numbers for sector counts will be limited to 1 TB (assuming 512-byte sectors, in turn assumed - as the only contemporary standard - by PS2 software).